Solar Hot Water: need advice

[karistote]

Hello everyone !

Here is the situation: I got 4 Vaillant brand tubular panels
and I want to use them to make solar hot water.

This type of product: https://www.vaillant.fr/accueil/produit ... e-320.html

But I only have the sensor panels

What do you recommend to complete the installation?
I imagine that these panels require a heat transfer fluid, a balloon and a programmer?

Thank you for your information

[Forhorse]

To complete your installation, you of course need all the plumbing that goes with it.
- Connection pipes, fittings and their insulation.
- Tank with integrated exchanger coil or tank + external exchanger.
- transfer group (circulator with non-return valve, filling / pure valves, flow control valve, flow meter)
- expansion tank + safety valve for the solar circuit.
- Heat transfer fluid (distilled water + antifreeze) PCMB makes it very good.
- regulation (at least a differential thermostat and its 2 probes)
- safety group for the cold water inlet of the tank (as for all tanks)
- thermostatic mixer for the hot water outlet from the tank (compulsory for safety reasons since the hot water in the tank can reach and exceed 80 ° C)

[karistote]

Thank you very much,

I will be inspired by your beautiful and very clear list!

[Did67]

- transfer group (circulator with non-return valve, filling / pure valves, flow control valve, flow meter)

Fill / purge valves, of course.

I think that with modern low consumption circulators, with adjustable power, you can skip the flow control valve and the flow meter ...

You adjust the power ("speed") of your circulator so that the difference in flow temperature / return temperature is around fifteen degrees maximum. If it is significantly more, your fluid is too "slow" by not repatriating the calories quickly enough: the output drops because panels and pipes are too hot ... If it is significantly less, your system "grinds" and you wasted electricity ("gray energy") ...

[Forhorse]

- transfer group (circulator with non-return valve, filling / pure valves, flow control valve, flow meter)

I think that with modern low consumption circulators, with adjustable power, you can skip the flow control valve and the flow meter ...

No, on my installation, it is a "small" circulator and even with the lowest speed, the flow rate is too high compared to what is recommended.
I had to close the adjustment valve.
Otherwise you need a PWM circulator with a regulation that supports it ... it's not the same price. It is a choice to make.

[Did67]

Ah! Ceal then depends on the circuit. In my house, there is an adjustment valve, but it is fully open ... I regulate by the circulator. It is true that I cross two floors to go from the roof to the garage, with baffles ...

Now I wonder if a bit rate maybe too high ??? Aside from consuming electricity, repatriating calories with panels / circuits at the lowest possible temperature can only improve performance, I think.

As much, it is not advisable to exceed a difference of fifteen degrees upwards, so I do not see why "brake" down ????

But I am not a specialist - I would like someone to explain to me why ...

[Forhorse]

Ah! Ceal then depends on the circuit. In my house, there is an adjustment valve, but it is fully open ... I regulate by the circulator. It is true that I cross two floors to go from the roof to the garage, with baffles ...

Now I wonder if a bit rate maybe too high ??? Aside from consuming electricity, repatriating calories with panels / circuits at the lowest possible temperature can only improve performance, I think.

As much, it is not advisable to exceed a difference of fifteen degrees upwards, so I do not see why "brake" down ????

But I am not a specialist - I would like someone to explain to me why ...

I don't have the exact explanation, and I haven't tried too hard to understand. I just followed the recommendations of the technical sheet of my panels. You should see on the site of the apper ...
However, when I put into service, to carry out tests, I had left the maximum flow, and what I noticed is that the temperature of the panels made the "yoyo": at the beginning everything is cold, the panels heat up -> the circulator start-up delta has been reached -> as the circulation speed is too high, the panels cool too much and the circulator stops, and the cycle starts again ...
Is the performance better with the "good" flow a little constant loan, or with a flow in "yoyo" I do not know ...

[Did67]

[
However, when I put into service, to carry out tests, I had left the maximum flow, and what I noticed is that the temperature of the panels made the "yoyo": at the beginning everything is cold, the panels heat up -> the circulator start-up delta has been reached -> as the circulation speed is too high, the panels cool too much and the circulator stops, and the cycle starts again ...
Is the performance better with the "good" flow a little constant loan, or with a flow in "yoyo" I do not know ...

Ah yes !!! There, it is very coherent. And indeed, that can completely explain why we limit the flow ... If the delta of cut-off is not configurable (it is it on certain "boxes"), indeed, we have no choice !

For reasons of "durability" of the systems, whatever they are, one will always prefer continuous operations - for example, the thermal shocks are a principal source of wear (heat engines of generators make the equivalent of millions and million kms, because they run 24 hours a day at constant temperature ...).

So indeed, we will consider that the flow control valve is useful and that it is better to put it (contrary to what I wrote above).